Plotting Windrose from csv - python

I would like to plot a windrose from data in .csv file.
From the Windrose documentation, it looks like I need the wind speed, wind direction, and date as index column (csv here).
I tried multiple ways around it but always run into errors.
The error I have now: ufunc 'isfinite' not supported for the input types, and the inputs could not be safely coerced to any supported types according to the casting rule ''safe''
Should I just leave out the index column or what would be the best option to plot a windrose from csv?
from windrose import WindroseAxes
from matplotlib import pyplot as plt
import matplotlib.cm as cm
import numpy as np
import pandas as pd
from windrose import plot_windrose
df = pd.read_csv("Wind2.csv",index_col='Date', names = ["Date", "speed", "direction"], sep=";")
ws = df["speed"].values
wd = df["direction"].values
plot_windrose(df, kind='contour', bins=np.arange(0.01,8,1), cmap=cm.hot, lw=3)
plot.show()

You have missing data - for instance, in line 182970, you're missing speed data.
Try manually filtering or filling in the data, or try using pandas' filter function to remove the offending lines.

Related

visualising data with python of time series and float colmn

i have the following quastion-
What can you tell about the relationship between time and speed? Is there a best time of day to connect? Has it changed throughout the years?
this is my dataframedataframe
my columns
data
does any one have any suggestion on how i would aprouch this question ?
import pandas as pd
import numpy as np
import matplotlib.pyplot as plt
import seaborn as sns
%matplotlib inline
df = pd.read_csv('/Users/dimagoroh/Desktop/data_vis/big_file.csv', low_memory=False)
sns.lmplot(x="hours",y="speed",data=df)
im trying to do a plot but get this error i think i need to manipulate the hour column to a diffrent data type right now it is set as object
Please post the error you get. From the data I think you need to pass x="hour" and not x="hours". Also try
df.hour = pd.to_datetime(df.hour)

Can't choose a column of a data frame on Python

I'm trying to plot a figure on Python but I get a KeyError. I can't read the column "Cost per Genome" for some reason.
Here is my code:
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt
data = pd.read_csv("Sequencing_Cost_Data_Table_Aug2021 - Data Table.csv") #The data can be found here: https://docs.google.com/spreadsheets/d/1auLPEnAp0aI__zIyK9fKBAkLpwQpOFBx9qOWgJoh0xY/edit#gid=729639239
fig = plt.figure()
plt.plot(data["Date"],data["Cost per Genome"])
It looks like either you have interpreted the data wrong into the Dataframe, of made an error with the plot. Read this. It might help you further: https://matplotlib.org/stable/api/_as_gen/matplotlib.pyplot.plot.html
P.S. I couldn't acces your spreadsheet. It was request only

How do I assign a column in a csv file by python?

I have a CSV that I want to graph.
However, to get this graph, I need to first assign a column to a list (or array) and then go on from there. I need to assign the first column to said list. In the said column, there are many repeats of the numbers 1 through 45 (so in code that would be range(1,46)).
Currently, I have written this so far:
for weekly sales against Date
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
%matplotlib inline
a = []
for stn in range(1,46):
a.append(walmart[walmart.Store == stn])
for printval in range(1,46):
b = a[printval-1]
NOTE: walmart (the value associated to the dataset) has already been read here by pd.read_csv. It works and an output has been made.
I do not know what to do from here. I want to graph this as well based on the store.
The data set can be found: https://www.kaggle.com/divyajeetthakur/walmart-sales-prediction
There are many ways to do this but the easiest that comes to mind is using pandas dataframe
First you need to install it in your environment. I see you tagged anaconda so this would be something like:
$ conda install pandas
Then import them in your python file (presumingly Jupyter notebook)
import pandas as pd
Then you would import the csv into a dataframe using the build in read_csv function (you can do many cool things with it so checkout the docs)
In your case assume you want to import just columns say number 3 and 5 and then plot them. If the first row in your csv contains the header (say 'col3'and 'col5') this should be read automatically and stored as the column name(If you want to skip the header reading add the option skiprows=1, if you want the columns to be named something else use the option names=['newname3', 'newname5']
data = pd.read_csv('path/to/my.csv', usecols=[3,5], names=['col1', 'col2'])
Then you can access the columns by name and plot them using data['colname']:
import matplotlib.pyplot as plt
plt.scatter(data['col1'], data['col2'])
plt.show()
Or you can use the built in function of pandas dataframes:
data.plot.scatter(x='col1', y='col2)
I have found out what I need to do to get this to work. The following code describes my situation.
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
%matplotlib inline
a = []
for stn in range(1,46):
a.append(walmart[walmart.Store == stn])
for printval in range(1,46):
b = a[printval-1]
w = b[b.Store == printval]
ws = w["Weekly_Sales"]
tp = w["Date"]
plt.scatter(tp, ws)
plt.xlabel('Date')
plt.ylabel('Weekly Sales')
plt.title('Store_' + str(printval))
plt.savefig('Store_'+ str(printval) + '.png') #To save the file if needed
plt.show()
Again, I have already imported the CSV file, and associated it to walmart. There was no error when doing that.
Again, the dataset can be found in https://www.kaggle.com/divyajeetthakur/walmart-sales-prediction.

Plotting from excel to python with pandas

I am new to python,pandas,etc and i was asked to import, and plot an excel file. This file contains 180 rows and 15 columns and i have to plot each column with respect to the first one which is time, in total 14 different graphs. I would like some help with writing the script. Thanks in advance.
The function you are looking for is pandas.read_excel (Link).
It will return a DataFrame-Object from where you can access your data in python. Make sure you Excel-File is well formatted.
import pandas as pd
# Load data
df = pd.read_excel('myfile.xlsx')
Check out these packages/ functions, you'll find some code on these websites and you can tailor it to your needs.
Some useful codes:
Read_excel
import pandas as pd
df = pd.read_excel('your_file.xlsx')
Code above reads an excel file to python and keeps it as a DataFrame, named df.
Matplotlib
import matplotlib.pyplot as plt
plt.plot(df['column - x axis'], df['column - y axis'])
plt.savefig('you_plot_image.png')
plt.show()
This is a basic example of making a plot using matplotlib and saving it as your_plot_image.png, you have to replace column - x axis and column - y axis with desired columns from your file.
For cleaning data and some basics regarding DataFrames have a look at this package: Pandas

How to refer/assign an excel column in python?

I have a csv file (excel spreadsheet) of a column of roughly a million numbers in column A. I want to make a histogram of this data with the frequency of the numbers on the y-axis and the number quantities on the x-axis. I'm using pandas to do so. My code:
import pandas as pd
pd.read_csv('D1.csv', quoting=2)['A'].hist(bins=50)
Python isn't interpreting 'A' as the column name. I've tried various names to reference the column, but all result in a keyword error. Am I missing a step where I have to assign that column a name via python which I don't know how to?
I need more rep to comment, so I put this as answer.
You need to have a header row with the names you want to use on pandas. Also if you want to see the histogram when you are working from python shell or ipython you need to import pyplot
import matplotlib.pyplot as plt
import pandas as pd
pd.read_csv('D1.csv', quoting=2)['A'].hist(bins=50)
plt.show()
Okay I finally got something to work with headings, titles, etc.
import matplotlib.pyplot as plt
import pandas as pd
data = pd.read_csv('D1.csv', quoting=2)
data.hist(bins=50)
plt.xlim([0,115000])
plt.title("Data")
plt.xlabel("Value")
plt.ylabel("Frequency")
plt.show()
My first problem was that matplotlib is necessary to actually show the graph as stated by #Sauruxum. Also, I needed to set the action
pd.read_csv('D1.csv', quoting=2)
to data so I could plot the histogram of that action with
data.hist
Basically, the problem wasn't finding the name to the header row. The action itself needed to be .hist .Thank you all for the help.

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